I agree. If you want to do it within the 3d world I think it would be
rather easy. You need to set up a plane (often called an overlay plane)
which is parallel to the image plate. You can sychronize the image plate
transform to the view transform so when the view transform is changed, your
overlay transformation is changed. Then you would put a flat (constant Z)
POLYLINE shape in the overlay transform. You would have a behavior for
mouse changes and when you were in the "selection mode" you would alter the
shape, possibly in threesteps : set anchor, drag box, and finish selection.
Then you could build a bounding box by taking the shape coords, map them
back into worl coordinates, deepen the bounds by increasing Z and then check
to see what 3d shapes in your graph fall within the box.
It would be a fun little project.
Dave Yazel
Cosm Development Team
----- Original Message -----
From: J. Lee Dixon <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, November 07, 2000 11:33 AM
Subject: Re: [JAVA3D] 2d graphics in Canvas3D
Well, the J3DGraphics2D can be used for exactly what you are talking
about, though my experience is that is really brings down the
performance of the renderer, and you have to keep the renderer going
since the user is dragging his mouse to create his ROI rectangle.
Here are a couple ideas:
If there are no animations or behaviors that you care to have running
while the selection is ocurring, you could: 1) take a snapshot of the
scene, 2) stop the renderer, 3) draw the snapshot and the rectangle as
the user draws it over the snapshot, 4) when the selection is done, turn
the renderer back on
Another idea is to draw the ROI rectangle IN the 3D scene, so the
rectangle will be redrawn as the user drags the mouse.
-Lee
-----Original Message-----
From: Karsten Fries [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, November 07, 2000 10:52 AM
To: [EMAIL PROTECTED]
Subject: [JAVA3D] 2d graphics in Canvas3D
Hi there,
i am supposed to do a 2d selection (spawning a rectangle) to define a
region
of interest for zooming purpose. So i wonder, if there is a possibility
to draw
into the canvas3d component without the whole scene being rendered while
the user
defines the roi.
I saw there is a class named J3DGrpahics2D. Can i use this. A short look
at it was
not encouraging at all.
Any suggestion are welcome
Best regards
Karsten
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